Method for producing oximes



3,185,732 METHOD FGR PRODUCING XIME Pierre Bapseres and Christos Nicolaides, Pau, France,

assignors to Socit National des Petroles dAquitaine,

Paris, France, a corporation of France No Drawing. Filed July 11, 1%2, Ser. No. 209,264

(Ilaims priority, application France, Mar. 6, 1962,

890,097 '8 Claims. (Cl. 260-566) The present invention relates to the preparation of hydroxylamine and its derivatives and, particularly, oximes. A very advantageous application of the invention is the preparation of oximes of cycloaliphatic ketones.

Hydroxylamine, in the form of salts or substituted derivatives, such as the suphate and sulphonates, is often employed at present forthe preparation of oximes. The oximes of cyclohexanone or methyl-cyclohexanone are prepared and then, when subjected tothe Beckmann transformation, produce the corresponding caprolactams, which are materials of prime importance in the preparation of polyamides. This preparation, however, requires oximes of considerable purity. Consequently, the hydroxylamine compound used, as well as the ketone, should also be pure. v

The present invention makes it possible to employ the so-called Raschig-reaction, which involves the reaction between a soluble nitrite, .a sulphite, and S0 to produce a hydroxylamine with a more or less impure bisulphite and/or sulphite solution. The invention permits use of aqueous solutions obtaining during the washing of various industrial gases containing S0 and possibly also H 8. Such industrial gases include oven gases, coke effluents,

gases from gas works, metallurgical installations, and

residual gases frornthe preparation of sulphur by the ited st te Pat 0 Claus process. The ability to use these gases constitutes an important industrial advance. Also, the process according to the invention dispenses With cooling of the reaction medium to 0 C. which has been necessary during the Raschig reaction and permits better results to be obtained at ambient temperature that at 0 C.

In making use of the invention in the preparation of oximes, especially those of cycloaliphatic ketones, one obtains the advantage of an improvement in the purity of the ketone used. It also makes it possible to effect hydrolysis and oximation of the compound obtained from the hydroxylamine used in a single operating phase in the same apparatus. The process of the invention can also simplify, if desired, the preparation of the oxime by carrying out the Raschig reaction, hydrolysis and oximation Within the same aqueous solution and in the same vessel. I

. To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully'describedand particularly pointed out in the claims, the following description setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principles of the invention maybe employed.

The invention consists, in a generalway, in treating a solution of a sulphite with at least one ketone or] aldehyde in order toform the corresponding sulphite compound and in then reacting the sulphite compound of the ketone or aldehyde with a nitrite'and suphur dioxide.

Although the sulphite or bisulphitecompounds are generally soluble in. water, it is often possible to bring about their precipitationby suitable adjustment of various factors. I For example, one or more'of the following conditions can be modified for this purpose: (1) higher concentration of sulphite and/or bisulphite in solution,

. 3,185,732 Patented May 25, 1965 p 2 (2) addition ofsubstances decreasing the solubility of the bisulphite compounds, such as alcohols and mineral salts such as ammonium sulphate, and (3) cooling the solution.

It thus becomes possible to precipitate (in the form of the bisulphitecompound of cyclohexanone) the bisulphite and sulphite contained in a solution of .an alkali metal, alkaline earth and/or ammonium sulphite, bisulphite and thiosulphate solution. The precipitate contains only the bisulphite to the exclusion of the other compounds of the solution treated and in particular thiosulphate. This is important because, if the same initial solution is used for the Raschig reaction in the usual manner, the hydroxylamine sulphonate is obtained in an amount (relative to the nitrite) which is lower when the content of thiosulphate is higher. The latter, in fact, needlessly takes up the nitro group.

According to one important embodiment, the bisulphite compound is separated from the initial solution, dried, and (if required) washed. It is then dissolved in water in a suitable medium for reaction with a soluble nitrite, (particularly an alkali metal, alkaline earth metal or ammonium nitrite) and with $0 which is passed into the solution. the cation present, for example ammonium, is thus obtained in solution containing the initial-ketone.

'When the object of the operation is to prepare the hydroxylamine, this may be separated from the ketone solution.

When, however, it is desired to form the correspondphite compound) is considerably improved by the addition to the medium of a small quantity of thiosulphate. Surprisingly enough, tests show that the presence of thiosulphate considerably improves the 'oximation. In

, obtaining the hydroxylamineby the standard process,

in the basence of the ketone, the yield is poor when the concentrations of thiosulphate are high.

In carrying out the invention, it is particularly suitable to employ ammonium salts, such as ammonium bisulphite and nitrite. In this way only ammonium sulphate (useful as fertilizer) needs to be recovered after the final neutralisation. 7

According to a preferred embodiment of the preparation of the hydroxylamine, nitrous vapors are used instead of the nitrite. These vapors are introduced into an arnmoniacal solution of the bisulphite compound of the ketone or aldehyde chosen. The nitrous vapors can be produced by any known means. They are advantageously formed by controlled oxidation of NH giving an NO/NO ratio of between 1.5 and 0.8, preferably The solution (which has absorbed the requisite'proportion of nitrous vapors) is then subjected to the action of sulphur dioxide. This-latter gas may be in the pure The hydroxylamine disulphonate of cyclohexa none at the ambient temperature.

tion of S can take place at temperatures up to 35 C., while in the old process it is necessary to keep the temperature as near as possible to 0 C. The preferred range, according to the present invention, is from 15 to 25 C.. In practice, the ambient temperature would be used, preferably around 20 C. Having begun the treatment with S0 on the solution at pH 7.5 to 8, the reaction is stopped when the pH has dropped to below 5 and in 'practice to around 3. At this time, the solution contains the initialketone and the hydroxylamine ammonium disulphonate which has been formed. It is desirable to remove the excess sulphurous gases which are present by. entrainment in an inert gas, such as air, nitrogen, smoke or the like, in known manner.

In order to produce the oxime in the solution obtained from the foregoing operations, it is advisable to proceed first with hydrolysis of the disulphonate into the monosulphonate. This hydrolysis occurs spontaneously at the ambient temperature. ated by heating, if desired up to 100 C. and preferably around 50 C. At the latter temperature, the hydrolysis takes place in about 1 to 1 /2 hours.

The reaction between the hydroxylamine ammonium monosulphonate and the ketone present (particularly in the case of cyclohexanone) takes place very rapidly in 1 to 1 /2 hours in the same medium, at around 15 to C. Consequently, if the hydrolysis has taken place above this'temperature, it is only necessary to al low the solution'to cool while it'is being agitated, so as to obtain the desired oxime by precipitation following neutralisation with ammonia. However, as indicated above, the yield of .oxirne is improved by the addition ly, according to a preferred form' of the invention, the

It can be acceler-' reaction medium contains thiosulphate, particularly in a proportion corresponding to a molar ratio of thiosulphate to bisulphite compound of 0.05 to 0.2 and preferably 0.1. For instance, the yield of oxirne with respect to the bisulphite compound is in the order of without thiosulplate but exceeds, 80% in the presence of thiosulphate.

Itwillfbe seen from the foregoing that, by starting (1.2 moles) and OL-lmole of ammonium thiosulphate were added to this solution. A stream of nitrous vapors (NO/N0 molar ratio=1.0) was introduced into the agitated solution which was cooledv to around 20 C. by a" circulation of water. The operation lasted for about 1 hour and consumed 1.6 moles of NO. The flow of gas was stopped when the pH reached the value of 7.5. Then, while still at 20 C., a stream of pure S0 was introduced at a rate of 37 liters per hour for minutes. The final pH was 3.

After 48 hours of hydrolysis and oximation at the ambient temperature, the solution was neutralised with 310 milliliters of 5 normalammonia. The weight of dry cyclohexanone-oxime obtained was 88 grams, reperenting a molar yield in relation to the bisulphite compound of 78%.

Example 2 Operation was carried out under the same conditions as those of Example 1, except for the entire absence of thiosulphate. The consumption of nitrous vapors was reduced to 1.3 moles, but the weight of oxirne fell to 57 grams, representing a molar yield of 50.5% with respect to the bisulphite compound.

Example 7 3 Operation was carried out under the same conditions as Example 1, except that the hydrolysis and oximation phase was'carried out at 50 C. for 2 hours 30 minutes. The yield of oxime was 72%.

Example 4 Example 5 One liter of liquor containing 5.9 moles of ammonium bisulphite was treated with 5.9 moles of methylcycloheXanone at room temperature, the mixture being agitated. The precipitate was filtered, dried, and washed. One mole of the precipitate was then dissolved in a liter of water and 1.2 moles of NNH OH and 0.1 mole of i ammonium thiosulplrate were added to the solution. A

and concentration of the bisulphite solution and on the f particular ketone or aldehyde employed, it may be advantageous to carry out all the operations in the initial The invention is typified by the following examples given by way of illustration:

Example 1 One liter of sulphite liquor containing5.9 moles of ammonium bisulphite was treated with 5.9 moles of The mixture was vigorously agitated. The bisulphite compound precipitated and was filtered, dried and washed.

The weight of precipitate. obtained was #1050 grams;

purity 97%. J

204- grams of this compound (1 mole) were dissolved in liter of Water. 84 of 14.3 N NH OH stream of nitrous oxide vapors with a NO/NO molar ratio of 1.0 was introduced into the agitated solution, the solution being cooled to around 20 C. The reaction lasted for an hour and consumed 1.6 moles of NO. The

'; stream of gas was stopped when the pH reached 7.5;

then, while still at 20 'C., a stream of pure SO was introduced at a rate of 37 liters per hour for 55 minutes. The final pH was 3.0. Hydrolysis and oximation took place for 48 hours at room temperature and then the a solution. was neutralized with 310 mils of 5 normal ampound of 78%.

tive to the bisulphite compound.

monia. The dry'methylcyclohexanone oxime obtained represented'a molar yield relative to the'bisulphite com- Example 6 The operation was carried out with methylcyclohexanane under the'same. conditions as in Example 5, except that the thiosulphate Was omitted. The consumption of nitrous oxide vapors was reduced to 1.3 moles, but the weight of oxime fell to a molar yield of 50.5% rela- Example 7 The operation was carried out with methylcyclohexanane under the same conditions asin Example 5, except that the hydrolysis and oximation phase was carried out at 50 C. for 2 /2. hours. The yield of oxime was 72%.

Example 8 nium nitrite and 0.1 mole of ammonium thiosulphate in 1 liter of water. This solution was treated with 80;; at 18 C. for 50 minutes at a rate of 37 liters per hour. The parts of the operation which followed were similar to thoseof Example 5, resulting in a molar yield of oxime with respect to the bisulphite compound of 80%.

Other modes of applying the principles of the invention may be employed, change being made as regards the details described, provided the features stated in the following claims, or the equivalent of such, be employed.

The invention having been thus described, what is claimed as new and desired to secure by Letters Patent is: 1. A method for producing oximes, comprising the steps of (a) treating a solution of bisulphite with a material selected from the group consisting of cyclohexanone and methylcyclohexanone to form a bisulphite compound of the said material, (b) adding thiosulphate in the amount of 0.05 to 0.2 mol of thiosulphate per mol of bisulphite present, subjecting the sulphite compound thus formed in an aqueous medium to nitrous oxide vapors at a temperature in the range from C. to +35 C.

until the pH is in the range from 7.5v to 8.0 and to sulphur dioxide at a temperature in the range from C. to 25 C. until the pH decreases to 3.0,

(d) hydrolyzing the resulting hydroxylamine ammonium disulphonate at a temperature in the range from 30 C. to 100 C., and

(e) subjecting the resulting solution to-oximation at room temperature with agitation in the presence of dissolved thiosulphate in the amount of 0.05 to 0.2 mol of thiosulphate per mole ofbisulphite present.

2. A method for producing oximes, comprising the steps of l (a) treating a solution of ammonium bisulphite with a cycloaliphatic ketone to form a bisulphite compound of the said material,

(b) separating the bisulphite compound from the solution,

(c) dissolving the bisulphite compound in Water and adding to the solution obtained a water soluble thiosulphate in the amount of from 0.05 to 0.2 mol per mol of bisulphite '(d) subjecting the solution thus formed to nitrous oxide vapors at a temperature in the range from 5 C. to +35 C. until the pH is in the range from 7.5 to 8.0 and to sulphur dioxide at a temperature in the range from 5 C. to +35 C. until the pH decreases to an amount in the range from 3.0 to 5.0,

(e) permitting the solution to stand 'for hydrolation of the resulting hydroxylamine ammonium disulphonate at a temperature in the range from 30 C. to 100 C. a

(f) subjecting the resulting solution to oximation at room temperature with agitation in the presence of the dissolved thiosulphate in the amount of 0.05 to 0.2 mol of thiosulphate per mol of bisulphite present,

(g) neutralizing the solution, and

(h) separating the oxime thus formed. I

3. A method for producing oximes, comprising the steps of (a) treating a solution of ammonium sulphite with a material selected from the group consisting of cyclohexanone and methylcyclohexanone to form a bisulphite compound of the said material,

in an aqueous medium containing dissolved thio sulphate in the amount of 0.05 to 0.2. mol of thiosulphate per mol of bisulphite present to a solution of nitrous oxide vapors at a temperature in the range (b) subjecting the bisulphite compound thus formedfrom -5 C. to +35 C. and sulphur dioxide, and (c) hydrolyzing the hydroxylamine ammonium disulphonate so formed at a temperature in the range from 30 C. to C. and maintaining the resultant solution at a temperature in the range from 15 C. to 25 C. with agitation to efiect oximation of the said material present by the monosulphonate.

4. A method for producing oximes, comprising the steps of (a) treating a solution of ammonium bisulphite with a material selected from the group consisting of cyclohexanone and methylcyclohexanone to form a bisulphite compound of the said material,

(b) subjecting the bisulphite compound thus formed in an aqueous medium containing 0.05 to 0.2 mol of a water soluble thiosulphate for each mol of bisul 'phite present to a solution of nitrous oxide vapors at a temperature in the range from 15 to 25 C. and sulphur dioxide, and

(c) hydrolyzing the hydroxylamine ammonium disulphonate so formed at a temperature in the range from 30 C. to 100 C. and maintaining the resultant solution at ambient temperature with agitation in the presence of the dissolved thiosulphate to effect oximation of the said material present by the monosulphonate.

5. A method for pnoducing oximes, comprising the steps of (a) treating a solution of ammonium bisulphite with a material selected from. the group consisting of 'cyclohexanone and methylcyclohexanone to form a bisulphite compound of the said material,

(1;) subjecting the bisulphite compound thus formed in an aqueous medium containing 0.05 to 0.2 mol of ammonium thiosulphate for each mol of bisulphite present to a mixture of nitrogen dioxide and nitric oxide vapors at a temperature in the range from 5 C. to +35 C. in whichthe molar ratio NO/NO is in the range from 0.8 to 1.5 and to sulphur dioxide until the pH decreases to a value in the range from 3 to 5, and

(c) hydrolyzing the hydroxylamine ammonium disulphonate so formed at a temperature in the range from 30 C. to 100 C. and maintaining the resultant solution at a temperature in the range from 15 to 25 C. with agitation in the presence of the dissolved thiosulphate to elfect oximation of the said material present by the monosulphonate. f6. A method for producing oximes, comprising the steps 0 (a) treating a solution of a bisulphite selected from the class consisting of sodium bisulphite, potassium bisulphite, and ammonium bisulphite with a material selected from the group consisting of cyclohexanone and methylcycl-ohcxanone to form a bisulphite compound of the said material, (b) subjecting the bisulphite compound thus formed in an aqueous medium containing a water soluble thiosulphate in the amount of 0.05 to 0.2 mol of thiosulphate per mol of bisulphite present to a compound selected from the group consisting of alkaline metal nitrites, alkaline earth metal nitrites and ammonium nitrite and to sulphur dioxide at a temperature from 5 C. to +35 C. until the pH drops to a value in the range from 3 to 5, and

(c) hydrolyzing the hydroxylamine ammonium disul .phonate. so formed at a temperature in the range from 30 C. to 100 C. and maintaining the resultant solution at a temperature in the range from 15 to 25 C. with agitation in the presence of the dissolved thiosulphate to efiect oximation of the said material present by the monosulphonate.

7. A method for producing oximes, comprising the steps of (a) treating a solution of a sulphite selected from the present to a mixture of the solution and sulphur dioxide and nitrous oxide vapors at a temperature in v the range from to 25 C. and the pH drops to a value in the range from 3 to 5, and

(c) hydrolyzing the hydroxylamine ammonium sulphonate so formed at a temperature in the range from 30 C. to 100 C. and maintaining the resultant solution at room temperature with agitation in thew presence of the dissolved thiosulphate to effect oximation of the said material present by the monosulphonate.

8. A method of producing oximes, which consists in (a) treating a solution of ammonium bisulphite with a ketone selected from the class consisting of cyclohexanone and methylcyclohexanone to 'form a bi sulphite compound of the ketone,

(b) separating the bisulphite compound from the solution, V I

(c) dissolving said bisulphite compound in Water and adding to the solution obtained 0.05 to 0.2 mol of ammonium thiosulphate per mol of the bisulphite present,

(d) subjecting the solution thus formed to a soluble nitrite selected from the group consisting of alkali metal, alkaline earth metal and ammonium nitn'tes in which the molar ratio NO/NO is in-the range from 0.8 to 1.5, at a temperature in the range from 15 to 25 C. until the pH of the solution is in the range of 7.5 to 8.0, and to sulphur oxide at 15 to 25 C. until the pH decreases to about 3,

(e) permitting the solution to stand for hydrolation of the resulting hydroxylarnine ammonium disulphonate at a temperature in the range from C. to O,

(f) subjecting the resulting solution to oximation at room temperature with agitation in the presence of the dissolved thiosulphate,

( g) neutralizing the solution, and

(h) separating the oxime thus formed.

References Cited by the Examiner UNITED STATES PATENTS CHARLES B. PARKER, Primary Examiner. 

1. A METHOD FOR PRODUCING OXIMES, COMPRISING THE STEPS OF (A) TREATING A SOLUTION OF BISULPHITE WITH A MATERIAL SELECTED FROM THE GROUP CONSISTING OF CYCLOHEXANONE AND METHYLCYCLOHEXANONE TO FORM A BISULPHITE COMPOUND OF THE SAID MATERIAL, (B) ADDING THIOSULPHATE IN THE AMOUNT OF 0.05 TO 0.2 MOL OF THIOSULPHATE PER MOL OF BISULPHITE PRESENT, (C) SUBJECTING THE SULPHITE COMPOUND THUS FORMED IN AN AQUEOUS MEDIUM TO NITROUS OXIDE VAPORS AT A TEMPERATURE IN THE RANGE FROM -5*C. TO +35*C. UNTIL THE PH IS IN THE RANGE FROM X.X TO 8.0 AND TO SULPHUR DIOXIDE AT A TEMPERATURE IN THE RANGE FROM 15*C. TO 25*C. UNTIL THE PH DECREASES TO 3.0, (D) HYDROLYZING THE RESULTING HYDROXYLAMINE AMMONIUM DISULPHONATE AT A TEMPERATURE IN THE RANGE FROM 30*C. TO 100*C., AND (E) SUBJECTING THE RESULTING SOLUTION TO OXIMATION AT ROOM TEMPERATURE WITH AGITATION IN THE PRESENCE OF DISSOLVED THIOSULPHATE IN THE AMOUNT OF 0.05 TO 0.2 MOL OF THIOSULPHATE PER MOLE OF BISULPHITE PRESENT. 